[PATCH RFC 08/11] rust: sync: Classless Lock::new() and pin_init()

Asahi Lina
2023-07-14T09:32:24Z

Use the new automagic lock class code to remove the lock class and name
parameters from Lock::new() and Lock::pin_init(). The old functions
are renamed to new_with_class() and pin_init_with_class() respectively.

The new approach uses the caller tracking machinery in Rust, which means
it can be trivially wrapped by adding #[track_caller] to any functions
that should bubble up lock class creation to their caller. This, for
example, allows a type using multiple Mutexes to create separate lock
classes for every user of the type, simply by adding that attribute to
the mutex creation code paths.

Signed-off-by: Asahi Lina <lina@asahilina.net>
---
rust/kernel/sync/lock.rs | 42 +++++++++++++++++++++++++++++++++++----
rust/kernel/sync/lock/mutex.rs | 4 ++--
rust/kernel/sync/lock/spinlock.rs | 2 +-
3 files changed, 41 insertions(+), 7 deletions(-)

diff --git a/rust/kernel/sync/lock.rs b/rust/kernel/sync/lock.rs
index 8e71e7aa2cc1..8849741c1d9a 100644
--- a/rust/kernel/sync/lock.rs
+++ b/rust/kernel/sync/lock.rs
@@ -5,7 +5,7 @@
//! It contains a generic Rust lock and guard that allow for different backends (e.g., mutexes,
//! spinlocks, raw spinlocks) to be provided with minimal effort.

-use super::LockClassKey;
+use super::{lockdep::caller_lock_class, LockClassKey};
use crate::{
bindings, init::PinInit, pin_init, str::CStr, try_pin_init, types::Opaque, types::ScopeGuard,
};
@@ -103,7 +103,40 @@ unsafe impl<T: ?Sized + Send, B: Backend> Sync for Lock<T, B> {}
impl<T, B: Backend> Lock<T, B> {
/// Constructs a new lock initialiser.
#[allow(clippy::new_ret_no_self)]
- pub fn new(t: T, name: &'static CStr, key: LockClassKey) -> impl PinInit<Self> {
+ #[track_caller]
+ pub fn new(t: T) -> impl PinInit<Self> {
+ let (key, name) = caller_lock_class();
+ Self::new_with_key(t, name, key)
+ }
+
+ /// Constructs a new lock initialiser taking an initialiser/
+ pub fn pin_init<E>(t: impl PinInit<T, E>) -> impl PinInit<Self, E>
+ where
+ E: core::convert::From<core::convert::Infallible>,
+ {
+ let (key, name) = caller_lock_class();
+ Self::pin_init_with_key(t, name, key)
+ }
+
+ /// Constructs a new lock initialiser.
+ #[allow(clippy::new_ret_no_self)]
+ #[track_caller]
+ pub fn new_named(t: T, name: &'static CStr) -> impl PinInit<Self> {
+ let (key, _) = caller_lock_class();
+ Self::new_with_key(t, name, key)
+ }
+
+ /// Constructs a new lock initialiser taking an initialiser/
+ pub fn pin_init_named<E>(t: impl PinInit<T, E>, name: &'static CStr) -> impl PinInit<Self, E>
+ where
+ E: core::convert::From<core::convert::Infallible>,
+ {
+ let (key, _) = caller_lock_class();
+ Self::pin_init_with_key(t, name, key)
+ }
+
+ /// Constructs a new lock initialiser given a particular name and lock class key.
+ pub fn new_with_key(t: T, name: &'static CStr, key: LockClassKey) -> impl PinInit<Self> {
pin_init!(Self {
data: UnsafeCell::new(t),
_pin: PhantomPinned,
@@ -115,8 +148,9 @@ pub fn new(t: T, name: &'static CStr, key: LockClassKey) -> impl PinInit<Self> {
})
}

- /// Constructs a new lock initialiser taking an initialiser.
- pub fn pin_init<E>(
+ /// Constructs a new lock initialiser taking an initialiser given a particular
+ /// name and lock class key.
+ pub fn pin_init_with_key<E>(
t: impl PinInit<T, E>,
name: &'static CStr,
key: LockClassKey,
diff --git a/rust/kernel/sync/lock/mutex.rs b/rust/kernel/sync/lock/mutex.rs
index 06fe685501b4..15ea70fa3933 100644
--- a/rust/kernel/sync/lock/mutex.rs
+++ b/rust/kernel/sync/lock/mutex.rs
@@ -13,7 +13,7 @@
#[macro_export]
macro_rules! new_mutex {
($inner:expr $(, $name:literal)? $(,)?) => {
- $crate::sync::Mutex::new(
+ $crate::sync::Mutex::new_with_key(
$inner, $crate::optional_name!($($name)?), $crate::static_lock_class!())
};
}
@@ -26,7 +26,7 @@ macro_rules! new_mutex {
#[macro_export]
macro_rules! new_mutex_pinned {
($inner:expr $(, $name:literal)? $(,)?) => {
- $crate::sync::Mutex::pin_init(
+ $crate::sync::Mutex::pin_init_with_key(
$inner, $crate::optional_name!($($name)?), $crate::static_lock_class!())
};
}
diff --git a/rust/kernel/sync/lock/spinlock.rs b/rust/kernel/sync/lock/spinlock.rs
index 979b56464a4e..9f6137f047ee 100644
--- a/rust/kernel/sync/lock/spinlock.rs
+++ b/rust/kernel/sync/lock/spinlock.rs
@@ -13,7 +13,7 @@
#[macro_export]
macro_rules! new_spinlock {
($inner:expr $(, $name:literal)? $(,)?) => {
- $crate::sync::SpinLock::new(
+ $crate::sync::SpinLock::new_with_class(
$inner, $crate::optional_name!($($name)?), $crate::static_lock_class!())
};
}

--
2.40.1